Trapezium

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Our Sun is a comfortable, middle-aged star. It's four-and-a-half billion years old, and astronomers expect it to continue in its present form for several billion years more.

If you have binoculars, you can see a group of young stars in the constellation Orion, which is in the east this evening. The stars are inside the Orion Nebula, a fuzzy blob of light in Orion's sword.

The nebula is a vast cloud of gas and dust -- a nursery where new stars are born. Four of these infant stars make up a pattern called the Trapezium, because it looks like the shape of a trapeze. Each of the stars is less than a million years old. That's a lot of years by human standards -- but the blink of an eye for a star.

The stars of the Trapezium are much brighter, hotter, and bluer than the Sun. Like the nebula itself, they're about 1500 light-years away. The brightest member of the quartet is just visible to the unaided eye, but you'll need binoculars to see the others.

If not for the Trapezium, we wouldn't see the Orion Nebula at all. The stars produce lots of ultraviolet energy, which is absorbed by the nebula's gas. This gives the gas a swift kick, boosting its energy level. When the atoms of gas return to their normal energy level, they emit visible light -- and the Orion Nebula shines brightly.

Look for the Nebula -- and the Trapezium -- inside Orion. It's in the east in early evening, and climbs high across the south during the night.

Script by Damond Benningfield, Copyright 2003, 2008

For more skywatching tips, astronomy news, and much more, read StarDate magazine.